Rotor type electric switch with resiliently mounted contact members



Aug. 24, 1965 R. s. TILLSON 3,202,775

ROTOR TYPE ELECTRIC SWITCH WITH RESILIENTLY MOUNTED CONTACT MEMBERS Filed Dec. 4, 1959 3 Sheets-Sheet l JNVEN TOR.

j ROBERT S.T|LLSON ATTORNEY Aug. 24, 1965 R. s TILLSON 3,202,7 75 ROTOR TYPE ELECTRIC SWITCH WITH RESILIENTLY MOUNTED CONTACT MEMBERS 5 Sheets-Sheet 2 Filed Dec. 4, 1959 INVENTOR. R OBE'RT S. TlLLsoN BY ATTORNEY (17?. S. TILLSON Aug. 24, 1965 3,202,775 ROTOR TYPE ELE TRIC SWITCH WITH RESILIENTLY MOUNTED CONTACT MEMBERS 3 Sheets-Sheet 3 Filed Dec. 4, 1959 INVENTOR. ROBERT S. I LLSON United States Patent 0 RUTQR ELEZITRF'Q SWITCH WEE-H REEIL- My invention relates to electric switches of the type which are enclosed in an outer enclosure and operated by manually operable means accessible externally of the enclosure. More particularly, the present invention relates to switches of the type including a base and an elongated contact shaft or rotor, carrying a plurality of movable contact members which are adapted to bridge or interconnect pairs of stationary contacts. Such switches have advantages over knife switch types of switches, in which a plurality of movable blades or contact arms are hinged or pivoted about a fixed pivot at one end, in that they provide a double-break action instead of only a sing.e break. By double-break it is meant that the current in each conductive path or pole is broken at two serially related points as compared with single break in which the path is broken at only one point. Such switches also have advantages over the type in which a plurality of bridging contact members are moved rectilinearly to bridge a pair of stationary contacts, in that they provide a pronounced wiping action in the switching operation which maintains a good contact surface.

According to the prior art, however, contact-rotor type switches have not been widely used because of various difficulties in their manufacture, operation and maintenance. Thus in prior art switches of this type, it has been relatively difiicult to remove and replace contacts. In rotor switches of the type including contacts of the knife-switch design, loss of contact-pressure is likely to occur, which interferes with proper operation. This occurs because such contact-pressure depends upon the resilience of the contact-jaws of the socket member, which is difiicult to maintain at a desired high level, especially without causing binding on the movable switch blade.

it is an object of the present invention to provide an electric switch of the double-break contact-rotor type having dependable and lasting contact pressure.

It is another object of the invention to provide a switch of this type in which the movable contactsmay be readily removed and replaced to facilitate inspection and/or replacement.

It is a further obiect of the invention to provide a switch of the double-break rotor type in which alignment of stationary contact surfaces is not critical to satisfactory operation.

A still further object of the invention is to provide a switch of this type in which contact pressure of each of the movable contact members will be maintained equally on each of the members of the pair of stationary contacts which it bridges.

It is another object of the invention to provide an enclosed electric switch in which the movable contacts are readily visible in the off position upon opening of the outer enclosure.

Another important object of the invention is to provide an electric switch in which the number of electrical connections in each conductive path or pole therethrough is reduced to a minimum.

Additional objects of the invention will in part be pointed out, and in part become obvious, from the following description of construction and operation of a particular embodiment.

In accordance with the invention in one form, an electric switch is provided including a base of molded insulating material. An insulating rotor is supported for rotation in the base, and a plurality of bridging switch members are provided, each of which is independently and resiliently supported in the insulating rotor. A pair of stationary contact members is provided for each of the bridging switch members. Each contact member has a cam surface portion arranged so that when the bridging switch member engages the stationary contact, continued rotation of the rotor cams each of the switch members laterally against its contact pressure spring.

In accordance with one aspect of the invention, the insulating rotor is movable to an on position and an off position, and also to a third position in which the rotor may be removed from the insulating base. The base is, furthermore, mounted in an enclosure and the rotor is releasably connected to an operating mechanism carried by the enclosure, which mechanism limits movement of the rotor to the off and on positions only.

The invention will be more fully understood from the following detailed description, and its scope will be pointed out in the appended claims.

In the drawings:

FIGURE 1 is a front elevation view of an electric switch in accordance with the invention, the cover of the enclosure being open and partly broken away;

FIGURE 2 is an exploded view of the terminal and contact portions of one pole of the switch of FIGURE 1;

FIGURE 3 is an exploded view in perspective of the rotor assembly of the switch of FIGURE '1;

FIGURE 3A is an enlarged view of a portion of the rotor assembly of FIGURE 3;

FIGURE 4 is a fragmentary elevational view of the switch of FIGURE 1 taken generally on the line 4-4 of FIGURE 1;

FIGURE 5 is a perspective view of a modified form of combination terminal and contact member.

In the drawings, the invention is shown as embodied in an electric switch including a generally rectangular enclosure 10. Mounted within the enclosure 10 and on the back wall thereof is a main insulating base 11 and a second, smaller, molded insulating base 12. The insulating basell serves as a switch base, and has a contact rotor 13 rotatably supported at one end 13A on the insulating base in a manner to be described. The opposite end 133 is not supported on the base 11, but projects beyond the side of the base at the right as viewed, and into an aperture in the operating member 14. The end 133 and the aperture in member 14 are of corresponding non-circular configuration. The operating member 14 is supported on a pivot pin 15 in the side wall of the enclosure 10 substantially aligned with the axis of the rotor 13. The member 14 is connected by means of a link 16 to a manually operable handle member 17 pivotally supported on a pivot pin 18, also in the side wall of the enclosure it). The end 13A of the rotor 13 is rotatably supported by two opposed, displaced, generally semi-circular, upper and lower bearing surfaces 2% and 21, at the left-hand end of the rotor, as shown particularly in FIGURE 3.

The mounting of the rotor 13 as described aiiords important advantages. Since the rotor is journalled on the base 11 only at the end 13A, small variations in the positioning of the switch base ll in the enclosure do not interfere with proper operation. The rotor 13, in other words, can vary slightly in its position with respect to the base 11 to compensate for variations in the relative positions of the bearing 26, 21 and the pivot 15 of the member 14. As will be further described, the function- 3 ing of the contact members is not adversely affected by such variations in positioning of the rotor.

A set of three line-terminal contact members 23 are mounted on the base 11 by suitable means, such as by screws 24, and each of the contacts 23 carries a wire connector 25 on an extension thereof (see FIG. 2). The construction of the line contact assembly is shown particularly at the right-hand portion of the exploded perspective view of FIGURE 2.

A set of fuse-terminal contacts 26 are likewise supported on the insulating base 11, by suitable means, such as by screws 27. Each of the contacts as includes a resilient spring clip member 28 attached thereto by means of a rivet 29. The spring clip 28 is spaced closely from a vertical wall portion of the contact 2 6 for the'purpose of receiving the blade of a fuse member 34.

It will be observed from FIGURE 1 that the contact portion of each of the terminals 26 serves a dual purpose. Thus one face of the vertical portion of the terminal serves as a contact for co-action with the movable contacts 39 in a particular manner, to be described. At the same time, the opposite face of this same portion of the terminal serves as a contact for the blade of the fuse 34. The necessity for a separate fuse-clip or a separate stationary contact is thereby eliminated.

A set of three load terminal members 343 are mounted on the secondary insulating base 12 by suitable means such as by screws 31. Each of the load terminals 30 comprises a generally L-shaped conductive member having an extension upon which a load wire connector 32 is mounted. A generally L-shaped spring clip member 33 is mounted adjacent each of the load terminals 30 and includes a portion spaced closely from the vertical portion'of the load terminals for the purpose of receiving the opposite end portion of the fuse 34. The spring clip member 33 includes a portion extending through an opening 35 in the molded base 12 and has a portion extending under the base 12 and attached thereto by the screw 31 which also holds the terminal 31} in position, all as shown in FIGURE 12.

The base 12 also includes an integral extension 12A on which are mounted a plurality of wire connectors 37 for the purpose of facilitating connection of neutral conductors, not shown. 'The rotor assembly is shown particularly in the perspective view of FIGURE 3. As shown in this figure, the 'rotor assembly includes an insulating rotor 13 and a 'plurality of bridging contact blades 38 corresponding in number and position to the pairs of stationary contacts 23, 26.

Each of the contact blades 38 includes a pair of wide, flat contact end portions 39 at the opposite ends thereof, each provided with a projecting arcing tip 39, leaving a "restricted central portion 441 which is circular in cross section. When assembled, each of the contact blades 38 is resiliently biased to a normal position by means of a fiat leaf spring 41 having a bowed configuration and having one end 41' bent inwardly and adapted to seat in the shallow recess 42 in one of the contact ends 39. The insulating rotor 13 has three enlarged hub portions 4-3, each of which has an aperture 44 therethrough. The configuration of the apertures 44 is shown particularly in FIGURE 3A which also includes a showing of the section of the contact blade and biasing spring. The aperture 44 includes an enlarged portion 45 and a reduced portion 46. The portions 44 and 45 are dimensioned so as to permit the insertion of the contact blade 38 when the blade portions thereof are maintained in a horizontal position. Following insertion of the contact blades in this manner, the blade may be rotated 90 degrees, in which position the shoulders ,of the contact portions retain the contact blade in position by engagement with the rotor. a I The contact blade 33 is resiliently maintained in this assembled position by means of the biasing contact spring 41 which is slid into position, being received in the portion 45 of the aperture 44 and having its ends bearing against the contact portions of the contact blade 3%, thereby biasing the central cylindrical portion of the contact blade against the curved shoulders 42; in the aperture 4 1.

The contact spring 31 is maintained in flatwise engagement with the end wall of the portion 45 of the recess 44 and has its opposite ends in engagement with the contact portions 39 of the contact blade. The result is that it maintains the contact blade 38 resiliently in the assembled condition illustrated, in which the major plane of the contact surface 39 is perpendicular to the axis of the rotor 13. At the same time, each of the blades 33 is permitted to rotate about the axis of the central porion 419 a small amount, and in addition, it is permitted to move a small amount in about an axis perpendicular to the axis of the rotor 13. In other words, while the contact blades each restrained from any movement about the axis of the rotor 13, each is permitted to move about other two axes in space extending perpendicular to the axis of the rotor. In addition, each of the contact blades 38 is permitted to move bodily and rectilinearly in the direction of the axis of the rotor 13.

Each of the contact blades 38 also includes a raised or embossed contact surface 39A, see FIGURE 1, located generally centrally of the contact portions 39.

The insulating rotor 13 includes a pair of flanges 49 at intermediate points, for the purpose of increasing the electrical oversurface clearance between adjacent contact members.

in addition, the rotor 13 includes a generally oblong or non-circular bearing member 5t; at an intermediate point. The bearing flange 59 is adapted to bear against the projections 51 of the base 11 during normal operation of the rotor between its off and on positions. This engagement prevents any movement of the insulating rotor axially toward the right as viewed at such times. During insertion and removal of the rotor, however, the rotor is rotated degrees with respect to its normal on position, to thev remove position R indicated in FIGURE 4 which permits it to pass between the projections 51, allowing the rotor 13 to be moved axially a short distance to the right, to permit the left end to clear the bearing surface 21).

In normal use, the rotor 13 is prevented from rotating 'a full 90 degrees away from the on position by means of its engagement with the operating member 14 of the operating mechanism. The rotor is disengaged from the operating member 14 by moving theentire switch assembly to the left within the enclosure 16*. The rotor assembly may therefore be easily inserted and removed in the switch base 11, and no separate fastening or retaining members are required.

Each of the stationary contacts 23 and 26 includes a generally planar main contact portion which has one portion 23A and 26A respectively, extending at an angle to the plane of the main portion and which act as a cam surface along which the movable contacts ride as the rotor is rotated. This action forces the contact blades 38 to the right as viewed in FIGURE 1, compressing the contact springs 41. Certain aspects of the invention in this connection are disclosed and-claimed in my divisional application Serial No. 195,774 filed May 18, 1962, now Patent No. 3,114,024 issued December 10, 1963, assigned to thesame assignee as the present invention.

The action of the contact springs 41 against the rotor 13 is such as to urge the rotor 13 for axial movement to the right as viewed in FIGURE 1. Such motion is prevented, however, as described above by the engagement of the bearing flange 51 with the stops 51 of the base 11. An effective contact pressure is therefore maintained, of the movable contact against the stationary contacts. It will also be observed that because of the mounting of the movable contact members, as described above,

lems are critical.

Moreover, the use of a bridging contact blade which resiliently engages only a single contact surface at each end and is resiliently biased by spring means at its center point overcomes theproblems involved in maintaining sufiicient contact pressure which are commonly encountered with the spaced contact jaw types of construction.

It will be observed, moreover, that since the engagement of the bearing flange S0 with the projections 51 prevents axial movement of the rotor to the right during switching operation, the contact pressure of each bridging contact pole is substantially independent of the contact pressure at any other pole. Thus, for example, any one of the bridging contact members 38 may be omitted to provide a two-pole switch, without affecting the contact pressure developed by theremaining two poles.

For the purpose of aiding in the cooling and extinguishing of arcs drawn by the contacts, there is furthermore provided an arc shield 53 for each of the stationary contacts 23 and 26, and retained on the insulating base 11 by means of screws 54. Each of the arc shields 53 is of generally U-shaped cross section and includes a plurality of open slots 55 in the bight portion thereof. The are shield members are preferably constructed of ferromagnetic material such, for example, as steel.

The insulating base 12 also includes an extension 123 provided with afpair of upstanding barrier portions 56 which serve to shield the fuses 34 from each other. The

base 11 has a similar extension 1113, including similar barrier portions 63.

The sub-base 12 is retained in the enclosure it by means of screws 57, and the insulating base 11 is maintained in the enclosure 10 by means of screws 53.

In FIGURE 5 there is shown a modified form of stationary load contact assembly comprising a stationary load contact member 58 having a generally planar contact portion 59 and a cam portion 59A and an integral fuse retaining portion 60. For the purpose of retaining acylindrical type of fuse ferrule in position against the portion 6 there is provided a resilient spring clip member 61 attached to the contact portion 58 by suitable means such as by'a rivet 62. It will be understood that when fuses of the ferrule type are used as contrasted to the type of fuse having a blade typeterminal, the retaining means mounted on the insulating block 12 would also be changed to correspond to the type shown in FIG- URE 5.

While I have shown only one particular embodiment of the invention, it will be readily apparent that many modifications thereof may be made by those skilled in the art, and I therefore intend by the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric switch comprising a base of insulating material, a plurality of pairs of stationary contact members mounted on said base in spaced apart relation, a contact rotor of insulating material mounted on said base, a plurality of movable contact members carried by said rotor in alignmentrespectively with each of said pairs of stationary contact members, said movable contact members each being movable independently of each of the other of said movable contact members in a first direction parallel to the axis of said rotor, said movable and stationary contacts including interengageable portions for camming said movable contact members in said first direction as said rotor is rotated, and separate biasing means resiliently biasing each of said movable contact members in a direction opposite to said first direction.

2. An electric switch comprising a base of insulating material, a plorality of pairs of stationary contacts mounted on said insulating base in spaced apart relation, an elongated contact rotor of insulating material supported for rotation on said base and having opposite ends, means carried by said rotor intermediate said ends engaging said base and preventing axial movement of said rotor during at least a portion of the rotational movement of said rotor, a plurality of movable contact members carried by said rotor in alignment with said pairs of stationary contacts respectively, each of said movable contact members being movable axially along said rotor, separate biasing means resiliently biasing each of said movable contacts against axial movement along said in a first direction, and cooperating cam means carried by said movable and stationary contacts for urging said movable contacts axially along said rotor in said first direction against said bias as said rotor is rotated.

3. An electric switch comprising a base of insulating material, a plurality of pairs of stationary contacts mounted on said insulating base in spaced apart relation, a contact rotor supported for rotation upon said base, a plurality of relatively movable contacts carried by said insulating rotor, a plurality of apertures extending transversely through said rotor, each of said movable contacts extending through one of said apertures in said rotor, said apertures each being elongated in a direction parallel to the axis of said rotor, a resilient spring member carried by said rotor biasing said contact members respectively to a predetermined position in said apertures, said stationary and movable contact including cooperating cam means for urging said movable contacts for movement axially along said rotor as said rotor is rotated, and means carried by said rotor and engaging said base for preventing axial movement of said rotor with respect to said insulating base during said movement.

4. An electric switch comprising an insulating base, a plurality of pairs of relatively stationary contacts supported on said base, an insulating rotor supported on said base, a plurality of relatively movable contact members carried by said insulating rotor in alignment with said pairs of stationary contacts respectively, each of said movable contacts comprising an elongated member having relatively wide thin flat end portions and a constricted intermediate portion, said rotor having a plurality of apertures extending transversely therethrough, each of said contact members being received in a corresponding one of said apertures, said contact members being rotatable within said apertures, and an elongated thin flat spring member in each of said aperture having a generally arcuate configuration with its mid-portion resting against said rotor and its end portions resting against said wide end portions of a corresponding contact member to limit rotation of said contact member and to bias said contact member to a predetermined position in said aperture.

5. An electric switch comprising a base of insulating material, a plurality of pairs of relatively stationary contacts supported on said base in spaced apart relation, an insulating contact rotor supported on said base for rotation about a predet rmined axis, a plurality of relatively movable contacts carried by said insulating rotor and corresponding in number and position to said pairs of stationary contacts, each of said movable contacts comprising an elongated conductive member having relatively wide thin fiat contact portions of predetermined width adjacent the opposite ends thereof and a relatively constrictecl central portion intermediate said contact portions, said rotor having an elongated aperture corresponding to each of said movable contact members, each of said apertures having a first dimension parallel to said axis of said rotor slightly greater than said width of said contact portion of said movable contacts whereby one of said contact members may be inserted in said aperture in a first con- Li dition with the plane of said contact portions extending parallel to said axis of said rotor, said contact members being rotatable within said apertures at least 90 degrees to a second condition following insertion, said apertures having a second dimension less than said width of said contact portions to prevent removal of said contacts when in said second condition, an elongated flat spring member of generally arcuate configuration within each of said apertures having its mid-portion resting against a portion of said rotor and its end portions contacting said end portions of said movable contact member respectively, said spring members limiting rotation of said contact members in said apertures to substantially less than 90 degrees.

6. An electric switch comprising a base of insulating material, a plurality of pairs of relatively stationary contacts supported in spaced apart relation on said base, a rotor of insulating material supported on said base, a plurality of relatively movable contacts carried by said insulating rotor, each of said contacts comprising an elongated conductive member having a pair of spaced projections thereon, said rotor having an aperture extending transversely therethrough corresponding to each of said movable contacts, each of said apertures having a noncircular outline whereby when one of said movable con for limiting rotation of said contact member to substantially less than 90 degrees, and means releasably holding said spring member in position in said aperture.

7. An electric switch as set forth in claim 6 wherein said means releasably holding said spring member in position in said aperture comprises a releasable interconnection between said spring member and said contact member.

8. An electric switch comprising a base of insulating material, a plurality of pairs of relatively stationary contacts supported in spaced apart relation on said insulating base, a rotor of insulating material supported on said base, a plurality of relatively movable contacts carried by said insulating rotor, each of said movable contacts comprising an elongated conductive member having relatively Wide thin flat end portions and an intermediate constricted portion, said rotor having an aperture corresponding to each said movable contacts, each of said movable contacts extending through a corresponding one of said apertures, each of said apertures having a dimension in the direction of the axis of said rotor slightly greater than the largest transverse dimension of said movable contacts and a dimension perpendicular to said axis of said rotor slightly less than the largest transverse dimension of said contact members, each of said movable contacts being rotatable at least 90 degrees when said constricted portion is within said aperture, an elongated spring strip member of generally arcuate configuration for each of said contact members, said resilient member being positioned within said aperture with the central portion thereof against said rotor and the end portions thereof contacting said end portions of said movable contact member, a depression in one of said contact portions receiving an end portion of said resilient member to prevent relative sliding move- -ment therebetween, the opposite end portion of said resilient member being slidable with respect to the corresponding end portion of said contact member, whereby each of said movable contact members may be inserted v 8 til said one endportion is received in said depression to resiliently retain said movable contact member and said resilient member in mounted relation'to said rotor.

9. An electric switch comprising a base of insulating material, a plurality of pairs of relatively stationary contacts mounted on said insulating base in spaced apart aligned relation, an insulating movable contact rotor rotatably supported on said base and extending transversely of said base between the members of said pairs of stationary contacts, a plurality of relatively movable contact members carried by said insulating rotor, each of said movable contact members comprising an elongated conductive member having relatively wide thin flat contact portions adjacent the ends thereof, the major plane of said contact portions extending perpendicular to the axis of said rotor, each of said stationary contacts comprising a conductive member having a generally planar contact surface extending parallel to the major plane of said movable contact members, said movable contact members being movable by rotation of said rotor between an open position in which said movable contact members do not interconnect said stationary contact members and closed position in which said movable contact members interconnect said stationary contact members, said movable contact members when in said closed position extending in side-by-side relation adjacent said stationary contacts and on the same side of both of said stationary contacts with respect to the axial direction of said rotor, the members of each pair of stationary contacts having their contact surfaces substantially aligned'in a common plane, each of said movable contact members having its contact portions substantially aligned in a common plane perpendicular to the axis of said rotor, the plane of the contact portions of each of said movable contact members when in said open position being displaced axially of said rotor with respect to the plane of said stationary contact members in a direction opposite to the direction of facing of the stationary contacts, whereby when said rotor is rotated, said movable and stationary contacts are moved axially relative to each other as said movable contacts move to said closed position, and resilient means tending to resist such relative movement of said contacts.

it An electric switch comprising a base of insulating material, a plurality of pairs of relatively stationary contacts mountedon said base in spaced apart aligned relation, an insulating contact rotor rotatably supported on said base and extending transversely of said base be tween the members of said pairs of stationary contact members, a plurality of relatively movable contactmembers carried by said insulating rotor, each of said contact members comprising an elongated conductive memer extending through an aperture in said rotor, said rotor being movable between a first position in which said movable contact members are out of contact with said stationary contact members and a second position in which said movable contact members are in contact with said stationary contact members, resilient spring means acting between said rotor and said movable contacts and biasing said movable contact members in a first direction into engagement with saidstationary contacts respectively when said rotor is in said second position, said resilient spring means also biasing said rotor for axial movement in a second direction opposite to said first direction, retaining. means carried by said rotor, said retaining means engaging said base and preventing axial movement of said rotor insaid second direction while retaining means is out of contactwith said base and permitting said rotor to move longitudinally in said second direction.

11. An electric switch comprising a base of insulating material, a plurality of relatively stationary contacts supported on said insulating base, a contact rotor supported on said insulating base, a plurality of movable blade type contact members carried by said rotor, said relatively stationary contacts each comprising a conductive strap portion mounted on said insulating base, said strap portion having a contact surface on one side thereof coacting with one of said movable contacts, first resilient spring means acting between said rotor and each of said movable contacts and biasing said movable contact against said contact surface, second resilient spring means mounted adjacent the surface of said strap portion directly opposite said contact surface, and receiving a conductive member by plug-in engagement between said resilient member and said opposite surface of said, strap portion.

12. An electric switch comprising a base of insulating .material, a plurality of relatively stationay contacts mounted on said insulating base, a plurality of movable contact members, means rotatably supporting said movable contact members on said insulating base, each of said movable contact members comprising a relatively wide thin flat blade-type contact member supported in edgewise relation to the general plane of said base, each of said stationary contacts comprising a relatively wide thin flat strap-type contact portion supported on said base in edgewise relation to thegeneral plane of said base and having its major planar surface parallel to said movable contact members, said contact portion of each of said stationary contacts having one major planar face thereof contacting a corresponding major planar face of one of said movable contact members in sliding relation, a first resilient spring member mounted in spaced apart relation to the face of said contact portion of each of said stationary contacts directly opposite said major planar face and receiving a fuse terminal in plug-in relation therebetween and to press said terminal in contacting relation against said opposite face, and a second resilient spring member acting between said means rotatably supporting said movable contact members on said base and each of said movable contacts and biasing said movable contact against said one major planar face of one of said stationary contacts.

13. An electric switch comprising a base of insulating material, an elongated contact rotor of insulating material pivotally supported on said base, a plurality of movable contact members carried by said rotor and spaced apart thereon in axial direction, a plurality of stationary contact members mounted on said base in spaced apart relation in a row along a line generally parallel to the axis of said rotor, each of said movable contact members including a portion engaging at least one of said stationary contact members when said rotor is rotated to on position, biasing means carried by said rotor and biasin b each of said contact members in a direction parallel to the axis of said rotor, stop means carried by said rotor for limiting the movement of said movable contact members under the force of said biasing means when said rotor is in said open position, said movable and stationary contact members including portionsengaging each other to cam said movable contact members axially along said rotor against the bias of said biasing means as said rotor is turned to said on position and camming said contact members away from said stop means.

14. An electric switch comprising a base of insulating material, an elongated contact rotor of insulating material rotatably mounted on said insulating base, said contact rotor being rotatable about a predetermined axis of rotation, said contact rotor having a plurality of apertures therethrough transversely of said axis and said apertures being displaced axially along said rotor, a movable contact member in each of said apertures and including a contact portion projecting radially of said rotor, said apertures being elongated in a direction parallel to said axis of said rotor, biasing means carried by said rotor biasing each of said movable contact members in a direction parallel to said axis, stop means carried by said insulating rotor limiting movement of said movable contact members under the force of said biasing means, a plurality of stationary contact members mounted on said insulating base and disposed in alignment in a row parallel to said axis of said rotor, each of said movable contact members engaging a corresponding one of said stationary contact members upon rotation of said rotor to said on position, said movable and stationary contacts each including cam surfaces camming said movable contact members axially of said rotor as said rotor is turned to said on position against the bias of said biasing means.

References Cited by the Examiner UNITED STATES PATENTS 1,010,069 11/11 Peat 200162 1,657,007 1/28 Douglas 200-3 1,730,599 10/29 Wulle 200-172 X 1,785,194 12/30 Hammerly 200-162 1,798,058 3/31 Besag 200-153 1,905,001 4/33 Sachs 200-3 1,967,523 7/34 Wurdack 200162 2,279,744 4/42 Shaw 200-114 2,290,516 7/42 William 200-153 2,458,511 1/49 Harlow 200114 2,885,516 5/59 Goudy et al 200-166 2,962,573 11/60 Scully 200-166 BERNARD A. GILHEANY, Primary Examiner. MAX L. LEVY, Examiner, 

1. AN ELECTRIC SWITCH COMPRISING A BASE OF INSULATING MATERIAL, A PLURALITY OF PAIRS OF STATIONARY CONTACT MEMBERS MOUNTED ON SAID BASE IN SPACED APART RELATION, A CONTACT ROTOR OF INSULATING MATERIAL MOUNTED ON SAID BASE, A PLURALITY OF MOVABLE CONTACT MEMBERS CARRIED BY SAID ROTOR IN ALIGNMENT RESPECTIVELY WITH EACH OF SAID PAIRS OF STATIONARY CONTACT MEMBERS, SAID MOVABLE CONTACT MEMBERS EACH BEING MOVABLE INDEPENDENTLY OF EACH OF THE OTHER OF SAID MOVABLE CONTACT MEMBERS IN A FIRST DIRECTION PARALLEL TO THE AXIS OF SAID ROTOR, SAID MOVABLE AND STATIONARY CONTACTS INCLUDING INTERENGAGEABLE PORTIONS FOR CAMMING SAID MOVABLE CONTACT MEMBERS IN SAID FIRST DIRECTION AS SAID ROTOR IS ROTATED, AND SEPARATE BIASING MEANS RESILIENTLY BIASING EACH OF SAID MOVABLE CONTACT MEMBERS IN A DIRECTION OPPOSITE TO SAID FIRST DIRECTION. 